In fourth generation (4G) long term evolution (LTE) cellular networks, user equipments (UEs) are required to adjust timing advance parameters when performing uplink data transmissions in order to compensate for differences in propagation delays. In this way, UEs that are positioned further from a base station transmit their uplink data transmissions slightly earlier than UEs positioned nearer to the base station so that the respective uplink data transmissions are synchronized upon being received by the base station. In general, uplink data transmissions are considered to be synchronized when cyclic prefixes (CPs) of the respective uplink transmissions at least partially overlap in the time domain upon arrival at the base station.
In order to determine the appropriate timing advance for initial uplink data transmissions in 4G LTE cellular networks, UEs transmit a preamble over a random access channel (RACH) to a base station. The base station uses the preamble to determine the appropriate timing advance parameter adjustment, which is fed back to the UE so that it can be used to perform the initial uplink data transmission. As used herein, an “initial uplink data transmission” refers to a data transmission that is performed by a UE that is initially accessing a cell, or was otherwise operating in an idle (or idle-like) state prior to performing the data transmission. In one embodiment, an “initial uplink data transmission” may be the first packet transmission for the UE upon arrival of a burst of multiple data packets.